If you decide to buy only the COVER of our poufs, you can also buy its interior at a later time. Polystyrene beads composed of 2% carbon and hydrogen and 98% air. It comes in the form of small breathable pearls. It does not contain CFCs and even less HCFCs, both of which are harmful to the ozone layer. It is 100% recyclable. Polystyrene is non-toxic and does not present any health risk because it does not release harmful substances. Fungi, bacteria and other microorganisms do not lurk there because it has no nutritional value. Its quality lasts over time.